OK, IMHO here goes....
IF you will only have six (6) handles that cut the service to your dwelling when you add the 2 pole cb for the EV charger feeder, you have NO NEC situation.
However, as Greg said, a load calc should/must be done to assure that the main service conductors are sufficient.
As your profile here says you are a PE/EE that should be no problem. You said that a 60 amp 2 pole feeds the house loads, and I'll guess you have HVAC and 2 'other 2 pole cb in the 'main' part of the split bus section.
As to your insurance co. request, do you have anything in writing, as to what they call 'electrical equipment'?
Perhaps, a new panel and AFCI breakers/GFI and a SPD ?? I can't see how they could say a 'rewire'! Maybe they would like a copy of any permits IF you had any electrical work performed??